Acetylene solution



Patented Jan. 19, 1954 T OFFICE ACETYLENE SOLUTION Harry M. Walker, Dickinson, Tex., assignor to Monsanto Chemical Company, St. Louis, Mo., a

corporation of Delaware No Drawing. Application November 5, 1952, Serial No. 318,950

This invention relates to acetylene and more specifically to acetylene solutions. This'invention also relates to the recovery of acetylene from an acetylene containing gas by means of a selective solvent.

It is known in the art that various organic compounds have shown utility as selective solvents for acetylene, thereby affordingmeans for storing acetylene in the form of solutions of acetylene in these solvents and means of extracting acetylene from gas mixtures or increasing the acetylene content of such gas mixtures.

It is an object of thi invention to provide a class of solvents having exceptional utility in the aforementioned applications. Other objects will become apparent from the description of this invention.

It has been discovered that the trimethyl esters of ortho aliphatic acids having the formula RCE (OCH3):

wherein R represents hydrogen or an alkyl radical containing from 1 to 3 carbon atoms, are excellent solvents for acetylene.

The Bunsen coeflicients (volume of gas, measured at C. and 760 mm. Hg, dissolved, at the temperature of the experiment, in one volume of solvent at a gas partial pressure of 760 mm. Hg) for acetylene in these solvents indicate their excellent solvent action for acetylene. The Bunsen coefiicients (a were determined in the following manner:

A quantity of acetylene was introduced into a calibrated flask and its initial pressure pi (measured to $0.05 mm. Hg), initial volume Vi (measured to :0.05 ml.), and initial temperature T1 (measured to 0.02 C.) determined. A quantity of solvent was then added to a second calibrated flask and its volume mls and vapor pressure PS determined. The acetylene was then transferred to the flask containing the solvent and, after agitation, the temperature of the liquid brought to a temperature of 25 i0.005 C. and the temperature of the gas brought to a temperature of 25.3i0.05 C. The pressure 20: of the gas, volume V: of the gas and temperature T: of the gas were then determined. a, was then calculated as follows:

273-2 P. (pr-r01 760ml, TgZ T12;

Claims. (01. 252-1) where un w in 80,000 Z: (Pf Pu P3 p I 22,4O0d,+a0MW.

where ds density of solvent at 25 C.

M wszmolecular weight of solvent pf p 8 In accordance with the procedure outlined above, the Bunsen coefiicient for acetylene at 25 C. in trimethyl orthoformate was found to be Per cent C2H2 8.5 Hz 51.4 N 1.6 CO 26.3 CH4 5.8 CO2 5.9 021-14 0.1 Heavier acetylenes 0.4

This gas stream is treated under pressure with the aforementioned solvents in any convenient manner well known to those skilled in the art as, for example, by countercurrent absorption in a suitable column. The solution of acetylene is then transferred to a suitable desorptio column where the pressure is released and the temperature raised. Concentrated acetylene is thus obtained and any contamination of the acetylene steam with the solvent is so small as to be insignificant.

In addition to the utility of these solvents in the extraction of acetylene from diluted acetyleneQthe Bunsen coefiicients of these solvents clearly indicate that they are particularly suited for storing acetylene under elevated pressures.

The solvents described herein may be used per se, or they may be used in mixtures with other acetylene solvents.

What is claimed is:

1. A composition ofm'atter comprising a solotion of acetylene in a trimethyl ester of an ortho aliphatic acid having the formula R-CE (OCH3)3 wherein R is selected from the;v group consisting: of'hydrogen and alkyl radicals contai i'lirig. from 1 to 3 carbon atoms.

2. A composition of matter'comprising, solu, tion of acetylene in trimethyl orthoformatg 3. A composition of matter comprising a solution of acetylene in trimethyl orthoacetat'e.

4. A composition of matter comprising a solution of acetylene in trimethyl orthopropionate'.

5. A composition of,.comprising a solu- 25 996,088;

tion of acetylene in trimethylorthobutyrate.

6. In a process for; the recovery of acetylene from an acetylene containing, gas, the step of treating said gas with a trimethyl ester of an wherein R is selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 3 carbon atoms.

7. In a process for the recovery of acetylene from an acetylene containing gas, thestep of treating, said. gas. with trimethyl orthoformate.

, 8?; In: a; process. for the, recovery Ofi acetylene from an acetylene containing gas, the step of treating said gas with trimethyl orthoacetate.

9. In a process for the recovery of acetylene from; an acetylene containing gas, the step of treating saidga with. trimethyl orthopropionate.

In'iprooess; for the recovery of acetylene Bour June 23,, L953 

1. A COMPOSITION OF MATTER COMPRISING A SOLUTION OF ACETYLENE AND IN A TRIMETHYL ESTER OF AN ORTHO ALIPHATIC ACID HAVING THE FORMULA
 6. IN A PROCESS FOR THE RECOVERY OF ACETYLENE FROM AN ACETYLENE CONTAINING GAS, THE STEP OF TREATING SAID GAS WITH A TRIMETHYL ESTER OF AN ORTHO ALIPHATIC ACID HAVING THE FORMULA 